This invention relates generally to filled bulk container transfer devices and more specifically to a new and improved filled bulk container transfer device permitting the safe translocation of heavy filled bulk containers from a location outside of the transfer device to a position within a base footprint of the transfer device, defined by anchoring points of the transfer device, where the filled bulk container can then be evacuated.
Large containers for the shipment of bulk material from one location to another have a capacity ranging from twenty cubic feet up to seventy-cubic feet and weighing from 700 to 3,300 pounds or more. With the introduction of large bulk containers, former methods of moving and evacuating them were displaced with transfer devices. Since the filled bulk containers can weight as much as 4,000 pounds, prior art transfer devices soon encountered problems with load stability and support.
Typical prior art transfer devices, as shown in FIGS. 1-3 of the drawings, were constructed in a manner where vertical frame members were anchored by securing base anchoring plates to a concrete floor or similar level horizontal surface. The upper portion of the transfer device had fixedly attached thereto a cantilevered beam which carried a movable lifting means whereby the filled bulk containers could be lifted from the floor or other surface and moved to a point inside the framework of the transfer device where the bulk container could then be evacuated.
The cantilevered beam was fixedly attached to the upper frame of the transfer device so that a portion of the cantilevered beam extended beyond the framework at the front of the transfer device. This allowed the operator to move the lifting means to the end of the cantilevered beam beyond the framework of the transfer device to a position above the filled bulk container which rested on the floor or a pallet. The operator could then connect the lifting means to the bulk container and activate the lifting means thus lifting the bulk container from the floor. At this point the entire weight of the bulk container would be located outside of, but supported by, the framework of the transfer device. This displaced weight caused a tremendous overturning moment on the vertical frame members of the transfer device and an upward moment or uplifting force on the rear base anchoring points of the vertical frame members. The resulting stress could cause the separation of the vertical frame members from the base anchoring plates or the separation of the base anchoring plates from the substrate.
The load stability of the transfer device when bearing the weight of a filled bulk container located outside of the framework depended on the stability of the joint where the vertical frame members were attached to the base anchoring plates, the anchoring means used to secure the base anchoring plates to the substrate and the integrity of the substrate into which the anchors were placed. An extremely heavy filled bulk container could easily overturn a transfer device by the overturning and uplifting moments created when initially lifting the bulk container from its resting place if the anchor design or the integrity of the frame member to anchor base plate joint failed for various reasons.
FIGS. 1, 2 and 3 of the drawings show the typical prior art transfer device with a filled bulk container located both inside and outside of the transfer device. FIG. 3 shows how the force of the downward weight of the filled bulk container creates an overturning moment on the transfer device and an upward moment or uplifting force at the base anchoring points of the vertical frames in the direction of the arrows as shown. These will be discussed more fully hereinafter in the Description of the Preferred Embodiment.